Results 1 to 2 of 2
  1. #1

    2010 VX Sport intake camshaft wear, bent exhaus valves, no compression in #2 & #4

    200 hour machine. Started to exhibit signs of loss of power (slower top end) in the last 50 hours or so. Put the ski up for 2 months, starting and running with out any issues. Went to start it (2 months later), to no avail. Was turning over slow. Thought is was a low batt. Not the case. Have no compression is #2 and #4 cylinders. (110 in 1 and 3 and ZERO in 2 and 4). Tore engine apart. Here is the strange part: 2 injectors are bad (letting air through). 2 exhaust valves bent. Middle lobes on ALL of the intake (cam) are completely wiped out. Not rough, just wiped out.
    My best guess: Injectors pumped fuel into the cylinders, hydrolocked #2 and #4, bending my valves.
    Camshft issue (completely separate). Either bad cam from the factory or an oil pump issue. However, the top end had plenty of oil and everything else looks 100%.
    I thought I knew these engines fairly well. Have 6 skis. But this one is a mystery.
    I can put in new valves, injectors and cam, but would like to know what can possibly cause this type(s) of failure at 200 hours. I've had machines (Yamahas) with 600 hours and no wear.
    They are used in salt water, but get flushed after every use and sit on a dry dock.
    Any help would be appreciated.

  2. #2
    Update: Cam must have been a bad run from Yamaha. No other explanation. Everything else in the top end is 100%. My best guess is that the valves hung up from sitting for 2 months. Piston smacked them back into place and bent 2 exhaust valves. Have parts on order. Even more perplexing:
    I swapped out a motor out of an 05 (which ran well just before the swap). Now the damn thing will not start. Checked every flipping thing (even the timing). I have YDS and everythign is within spec. I even swapped the power pack, the TPS and ECM. Nothing. Have excellent spark, good compression and plugs are getting fuel. I cycled the injectors, fuel pump, coils, etc... Does anyone know if the timing is different from 2005 to 2011 (ie: have to change the deg. of BTDC for the 2011 electronics to work). I would never imagine that Yamaha would do something like that, but I'm running out of ideas.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. WTB - Parts WTB 2010 or up INTAKE MANIFOLD.
    By 1_Fast_SHO in forum Yamaha Classifieds
    Replies: 1
    Last Post: 12-23-2012, 11:09 PM
  2. FS New Protec intake grate GP1200 non power valve
    By 111toybox in forum Yamaha Classifieds
    Replies: 0
    Last Post: 09-22-2011, 08:31 AM
  3. FS 2010 FX SHO Intake Grate
    By TJBrad04 in forum Yamaha 4 Stroke Skis
    Replies: 0
    Last Post: 11-30-2010, 03:07 PM
  4. 04 GTX SC I think I bent my valves.
    By mfvmx in forum 4-Tec Performance
    Replies: 3
    Last Post: 08-22-2010, 11:07 PM
  5. Bent Exhaust Valve 08 VX110 14 hrs
    By dcm554 in forum Yamaha Open Discussion
    Replies: 4
    Last Post: 06-12-2010, 03:48 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts